I'm trying to control a pin and set its logic level to '1' and then '0' (basically blinking an LED) but for some reason I can't even get this basic thing to work.
From digging around I found that I first need to set the bit/port to output mode and only then change the output level of the pin.
Here's my full code, and any sort of guidance would be very greatly appreciated.
#include <stdio.h>
#include <string.h>
#include "inc\C8051F120.h"
sbit ON_BOARD_LED = P2^0;
void main(void)
{
int i = 0;
P2MDOUT = 0xFF;
while(1)
{
for(i = 0; i < 10000; i++);
ON_BOARD_LED = 0;
for(i = 0; i < 10000; i++);
ON_BOARD_LED = 1;
}
}
Any ideas what I may be doing wrong or where I could get more relevant information?
Thank you in advance,
Matt
Consider changing the maximum value for the loop. I think it´s too fast to be seen if the C8051F120 runs at 100MHz. Change to at least 10^8 to blink one second on , another off.
Also check the following. From https://www.silabs.com/documents/public/data-sheets/C8051F12x-13x.pdf
"The output drivers on Ports 0 through 3 remain disabled until the Crossbar is enabled by setting XBARE
(XBR2.4) to a logic 1." page 239
Try adding XBR2 = 0x40; before the P2MDOUT = 0xFF;
For the Keil C51 compiler you can create a slightly more accurate delay as follows (note that how the compiler decides to optimize the C code can vary greatly depending on your settings, so you will need to calibrate it if they change!)
Busy loop:
#include <intrins.h>
void wait(volatile uint32_t cnt) {
while(cnt--)
_nop_();
}
From the Keil header file the port definition is:
sfr P2 = 0xA0; /* PORT 2 LATCH */
From the Keil compiler sbit page
sbit name = sfr-name ^ bit-position;
sbit name = sfr-address ^ bit-position;
sbit name = sbit-address;
So it seems your P2^0 is correct.
Related
I would like to measure a pulse using the pic 18f4550 in capture mode, this pulse is generated by the pic microcontroller itself, for this I use a function which plays the role of the XOR logic gate (you find the function that I've used below). with RC0 and RC2 the inputs and RC6 the signal output. the pulse leaving RC6 enters ccp2 to be measured.
The problem I found is that the ccp2 cannot detect the impulse generated by the microcontroller. I don't know if there are any conditions to connect the pins of the microcontroller or something.
If anyone has an answer or a hint to fix this, I will be grateful!
and if you have any questions feel free to ask .thanks !!
UPDATE: I changed some instructions in the code, now the RC6 output provides a signal. but my LCD does not display anything. the RC6 output is present below.
UPDATE 2: the while(1) in the xor() function blocking the rest of my program, so the program never get out of xor() and my LCD wont display anything. when I don't use the while loop in xor () my RC6 produce anything, the same for the LCD.
I don't know where the problem is, I did everything in my power to find the bug . but the system still not working!!!
I will leave the program as it is, so new readers can understand what I am talking about.
#include <stdio.h>
#include <stdlib.h>
#include "osc_config.h"
#include "LCD_8bit_file.h"
#include <string.h>
unsigned long comtage,capt0,x;
char pulse[20];
char cosinus[20];
float period,dephTempo,deph,phi;
void init (){
IRCF0 =1; /* set internal clock to 8MHz */
IRCF1 =1;
IRCF2 =1;
PIE2bits.CCP2IE=1;
PIR2bits.CCP2IF=0;
CCPR2 =0; /*CCPR1 is capture count Register which is cleared initially*/
T3CONbits.RD16=1;
T3CKPS0=0;
T3CKPS1=0;
TMR3CS=0;
TMR3IF=0;
T3CCP2=0; /*Timer3 is the capture clock source for CCP2*/
}
void xor()
{
while(1)
{
if (PORTCbits.RC0==PORTCbits.RC2)
{
PORTCbits.RC6=0;
}
else if (PORTCbits.RC0!=PORTCbits.RC2)
{
PORTCbits.RC6=1;
}
}
}
void main()
{
TRISCbits.TRISC0=1;
TRISCbits.TRISC2=1;
TRISCbits.TRISC6=0;
xor();
LCD_Init();
while(1)
{
CCP2CON = 0b00000101;
PIR2bits.CCP2IF = 0;
TMR3ON = 0;
TMR3 = 0;
while (!PIR2bits.CCP2IF);
TMR3ON = 1;
CCP2CON = 0b00000100;
PIR2bits.CCP2IF = 0;
while (!PIR2bits.CCP2IF);
comtage = CCPR2;
dephTempo = (((float)comtage /30.518)/65536 );
sprintf(pulse,"%.3f ",dephTempo);
LCD_String_xy(0,0,"the pulse width is : ");
LCD_String_xy(2,9,pulse);
}
}
I am using stm8l - discovery and i have created a code for toggling a led for every 1 second using timer (TIM1) but this is not working properly. I am missing something here in my configuration
I could enter the interrupt function for the first time but after that it does not enter the interrupt function. Someone please look into and help me out
enter code here
#include <iostm8l.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "defs.h"
unsigned int count = 0;
#svlreg #interrupt void TIM1(void)
{
count += 1;
TIM1_SR1 &= ~(0x01);
}
main()
{
CLK_DIVR = 0x00; // Set the frequency to 16Mhz
CLK_PCKENR2 = 0x02; // clock for timer1
PC_DDR = 0x80; // direction output for led
PC_CR1 = 0x80; // fast push pull mode
PE_DDR = 0x80; // direction output for led
PE_CR1 = 0x80; // fast push pull mode
TIM1_PSCRH = 0x3e; //to create a frequency for 1000 hz
TIM1_PSCRL = 0x80; // so prescalar is 16000
TIM1_CR1 = 0x01;
TIM1_IER = 0x01;
_asm("rim\n");
while(1)
{
if (count == 1000)
{
PE_ODR ^= 0x80;
count = 0;
}
}
}
The interrupt enters only one time but after that it does not enter. So variable "count" remains at value 1
You are using magic numbers for the bit masks instead of defined constants, so the code is pretty damn hard to read for you and me both. Change this so that the code ends up like for example
TIM1_SR1 &= ~TIM1_SR1_UIF;
Since this is a 8 bit MCU it is also absolutely essential that you u suffix all integer contants, or they will be of type signed int, which you don't want.
For example this code TIM1_SR1 &= ~(0x01); is equivalent to TIM1_SR1 &= -2. Very easy to write accidental subtle bugs this way. I recommend studying Implicit type promotion rules.
It is highly recommended to disassemble every ISR you write to see what machine code you actually end up with, and single step it through the debugger while watching the register as well. This particular register seems to ignore having 1 written to it, so you could probably just do TIM1_SR = TIM1_SR1_UIF;. Incorrectly cleared timer flags inside ISRs is one of the most common bugs in embedded systems.
Quoting the manual:
UIF: Update interrupt flag
– At overflow or underflow if UDIS = 0 in the TIM1_CR1 register
– When CNT is re-initialized by software using the UG bit in TIM1_EGR register, if URS = 0 and UDIS = 0 in the TIM1_CR1 register.
– When CNT is re-initialized by a trigger event (refer to the TIM1_SMCR register description), if URS = 0 and UDIS = 0 in the TIM1_CR1 register
Your code doesn't appear to do any of this, so it is pretty safe to assume the timer counter isn't reset.
Another problem is that count must be declared as volatile or otherwise the compiler might optimize out this code completely:
if (count == 1000)
{
PE_ODR ^= 0x80;
count = 0;
}
I am currently working on a project where we have to use an AVR ATMEGA328 micro-controller, specifically the USART peripheral, to control 8 LED's. We have to send commands to the micro-controller that will turn on, off, and blink the LED's at different rates. I have written a program in C that I think will do the job, but I would like someone to look at it and help me fix any mistakes that I may have. Your help will be greatly appreciated!
*P.S. Each command in the commands array associates with its corresponding LED state in the LED array. The LED's are connected to PORTB of the micro-controller.
#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
/* Arrays that contain all input commands and LED states */
const char *commands[] = {"ON0","ON1","ON2","ON3","ON4","ON5","ON6","ON7","ON8","OFF0","OFF1","OFF2","OFF3","OFF4","OFF5","OFF6","OFF7","OFF8","BLINK0","BLINK1","BLINK2","BLINK3","BLINK4","BLINK5","BLINK6","BLINK7","BLINK8","STOP"\0}
int LEDs[28] = {0X01,0X02,0X04,0X08,0X10,0X20,0X40,0X80,0XFF,0XFE,0XFD,0XFB,0XF7,0XEF,0XDF,0XBF,0X7F,0,0X01,0X02,0X04,0X08,0X10,0X20,0X40,0X80,0XFF,0}
int i;
int j;
int Blinky(int j); // Function to execute blinking commands where j is the argument
{
PORTB = LEDs[j];
_delay_ms[250 + (j-18) * 50]; /* Calculates blinking delay times */
PORTB = 0;
_delay_ms[250 + (j-18) * 50];
}
int main(void)
{
DDRB=0XFF; // PORTB is set to output
DDRD=0X02; // Turns on the transmit pin for the USART in PORTD
/* Setup USART for 9600,N,8,1 */
USCR0B = 0X18;
USCR0C = 0X06;
UBRR0 = 51;
sei(); // Enable Global Interrupts
char input;
if(UCSR0A & 0X80) /* Reads data from the USART and assigns the contents to the character input */
input = UDR0;
j=28;
char cmd;
cmd = *commands[i];
for(i=0; i<28; i++)
{
if(input==cmd) /* If the contents of UDR0 are equal to one of the commands */
j = i;
}
while(1)
{
if(j<18)
PORTB=LEDs[j]; // Executes the "ON" and "OFF" commands
else if(j<27)
Blinky(j); // Executes the blinking command by calling the Blinky function
else if(j=27)
PORTB=0; // Executes the "STOP" command
else
PORTB=0; // Accounts for typing errors
}
return(0);
}
There is a lot wrong with this program, but code review is not the purpose of Stack Overflow. See the FAQ for how to ask an appropriate question.
That said, some of the obvious problems are:
The _delay_ms() function needs to be called with a compile-time constant. It won't work correctly if the parameter needs to be calculated at run-time.
if you don't read any char from USART, then you still go through the rest of the loop.
char cmd declares a character variable, but then you assign a pointer to it.
i is used before it is set to a meaningful value.
input== cmd will likely never be true as one side is a character and the other is a pointer.
This question will likely close soon. Good luck, and come back if you have a question better suited to Stack Overflow.
Please help me with this code, it is making me crazy. This is a very simple program with 8-bit timer, cycling through all 8 leds (one-by-one). Am using ATSTK600 board.
My timers are working well, I think there is some problem with the loops (when I debug this program using avr studio-gcc, I can see all the leds working as I want but when I transfer it on board...leds don't blink). Am going crazy with this type of behavior.
Here is my code:
#include <avr/io.h>
#include <avr/interrupt.h>
volatile unsigned int intrs, i, j = 0;
void enable_ports(void);
void delay(void);
extern void __vector_23 (void) __attribute__ ((interrupt));
void enable_ports()
{
DDRB = 0xff;
TCCR0B = 0x03;
TIMSK0 = 0x01;
//TIFR0 = 0x01;
TCNT0 = 0x00;
//OCR0A = 61;
intrs = 0;
}
void __vector_23 (void)
{
for(i = 0; i<=8; i++)
{
while(1)
{
intrs++;
if(intrs >= 61)
{
PORTB = (0xff<<i);
intrs = 0;
break;
}
}
}
PORTB = 0xff;
}
int main(void)
{
enable_ports();
sei();
while(1)
{
}
}
Your interrupt routine is flawed. intrs counts only the number of times the loop has executed, not the number of timer interrupts as its name suggests. 61 iterations of that loop will take very little time. You will see nothing perceivable without an oscilloscope.
The following may be closer to what you need:
void __vector_23 (void)
{
intrs++;
if(intrs > 60)
{
intrs = 0;
PORTB = (0xff<<i);
i++ ;
if(i == 8 )
{
i = 0 ;
PORTB = 0xff;
}
}
}
Although setting the compare register OCR0A to 61 as in your commented out code would avoid the need for the interrupt counter and reduce unnecessary software overhead.
Are you sure that the code downloaded to the board is not optimized?
Have you attached volatile attribute to the PORTB identifier?
Is there a way for you to slow down the code (outside the debugger)? Any chance it's running but fast that you don't see it?
Can you verify that your intended code is in fact running (outside the debugger)?
When interrupt occurs, handler very quickly counts 62*9 times and finally sets PORTB to 0x00, so leds do only very short flash which is not visible. You see it in sumulator just because it runs slower and do not emulate visual dimming effect of fast port switching. Program has a design flaw: it tries to do full blinking cycle in single interrupt. That's wrong--only a single step should be performed in interrupt call. So handler should look like this:
void __vector_23 (void)
{
intrs++;
if(intrs >= 61)
{
PORTB = (0xff<<i);
intrs = 0;
i++;
if(i>8) i = 0;
}
}
Try this.
There is guidelin on interrupts handlers: Interrupt handler should be as fast and short as possible. Do not perform complex tasks in interrupts (cycle loop is one of them, if you get cycle in interrupt, try to remove it). Do not wait or delay in interrupts.
If you're seeing the behaviour you want when debugging with avr studio-gcc, then that gives you some confidence that your program is "good" (for some sense of the word "good"). So it sounds as though you need to focus on a different area: what is the difference between your debug environment and your stand-alone download?
When doing a stand-alone download, do you know if your program is running at all?
Are the LEDs blinking, or turning on at all? You don't explicitly say in your question, but that question could be very relevant to the debugging process. Does it look like the right behaviour, running at a different speed? If so, then your program is probably not doing some sort of initialisation that the debugger was doing.
When doing a stand-alone download, is the program being compiled with different settings compared to the debug version? Perhaps compiler optimisation settings are changing your program's timing characteristics.
(Your question would be better if you gave more detail about what the stand-alone download is doing. In general, it is hard for someone to debug a remote system when they're given few or no details about what is happening. Do all/some of the LEDs turn on at all?)
The connection is as follows An infrared sensor circuit which yields 0 or 5v depending on closed or open circuit output line to port 2_0 pin of microcontroller 8051 philips.Problem is when i do this the circuit value are overridden by the current value on port 2_0 led always goes on.Here is my code(in keil c) i guess i have not configured P 2_0 as input properly
void MSDelay(unsigned int);
sbit led=P1^0;
void main()
{
unsigned int var;
P2=0xFF;
TMOD=0x20;
TH1=0xFD;
SCON =0x50;
TR1=1;
while(1)
{
var=P2^0;
if(var==0)
{
led=1;
SBUF='0';
while(TI==0);
TI=0;
MSDelay(250);
}
else
{
led=0;
SBUF='9';
while(TI==0);
TI=0;
MSDelay(100);
}
}
}
EDIT : I was facing a problem since the 8086 processor i was using had a fault in it. Would recommend anyone trying this to get a few spares when programming.
jschmier has a good point. Also the port may not be configured correctly, or is there something in the circuit that is causing the led to toggle off and on very quickly so it looks like it is on all the time.
You typically use the sbit data type for P2_0 to define a bit within a special function register (SFR).
From C51: READING FROM AN INPUT PORT (modified)
sfr P2 = 0xA0;
sbit P2_0 = P2^0;
...
P2_0 = 1; /* set port for input */
var = P2_0; /* read P2_0 into var */
It is important to note that sbit variables may not be declared inside a function. They must be declared outside of the function body.
Another option may be to read all 8 pins of P2 and then mask off the unwanted bits.
char var; /* define 8 bit variable */
P2 = 0xFF; /* set P2 for input */
var = P2; /* read P2 into var */
var &= 0x01; /* mask off unwanted bits */
Rather than read P2 or the P2_0 pin into an unsigned int (16 bits), you could use a char (8 bits) or single bit to save on memory.
char var;
...
var = P2;
or
bit var;
...
var = P2_0;
Another option may be to make the char bit-addressable.
char bdata var; /* bit-addressable char */
sbit var_0 = var^0; /* bit 0 of var */
...
var = P2; /* read P2 into var */
if(var_0 == 0) /* test var_0 (bit 0 of var char) */
{
...
}
You can find additional useful information in the Keil Cx51 Compiler User's Guide and related links.
Note: Most of my 8051 experience is in assembly. The C examples above may not be 100% correct.
Thank you so much... my coding works
And I learn how to define input port and read the data
#include<reg51.h>
#define opp P1
#define ipp P0
sbit op =P1^0;
sbit ip =P0^0;
main()
{
unsigned int value;
P0=0xFF;
value=P0;
value &=0x01;
if(value==0)
{
P1=0x01;
}
else
{
P1=0x00;
}
}